<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title>color颜色</title>
    <style type="text/css">
        .one{
            color:red;
        }
        .two{
            color:#FF0000;
        }
        .three{
            color:rgb(255,0,0); /*color:rgb(100%,0%,0%);*/
        }
    </style>
</head>

<body>
    <a href="https://www.imooc.com/" class="one">慕课网1</a>
    <a href="https://www.imooc.com/" class="two">慕课网2</a>
    <a href="https://www.imooc.com/" class="three">慕课网3</a>
</body>

</html>